/*
 * @Author: pmy
 * @Date: 2022-07-14 09:47:39
 * @LastEditors: pmy
 * @LastEditTime: 2022-07-14 09:48:26
 * @FilePath: \bdcar-net\src\assets\instruct\v-dialogDrag.js
 * @Description: 
 * Copyright (c) 2022 by pmy/exsun, All Rights Reserved. 
 */
import Vue from "vue";
Vue.directive("dialogDrag", {
    bind(el, binding, vnode, oldVnode) {
      const dialogHeaderEl = el.querySelector('.dialog-title');
      const dragDom = el.querySelector('.el-dialog');
      if(!dialogHeaderEl){
        return
      }
      dialogHeaderEl.style.cursor = 'move';
      // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
      const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);
      dialogHeaderEl.onmousedown = (e) => {
        // 鼠标按下，获取鼠标在盒子内的坐标
        const disX = e.clientX - dialogHeaderEl.offsetLeft;
        const disY = e.clientY - dialogHeaderEl.offsetTop;
        // 获取到的值带px 正则匹配替换
        let styL;
        let styT;
        // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
        if (sty.left.includes('%')) {
          styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);
          styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100);
        } else {
          styL = +sty.left.replace(/px/g, '');
          styT = +sty.top.replace(/px/g, '');
        }
        // 鼠标移动的时候，把鼠标在页面中的坐标，减去鼠标在盒子内的坐标就是模态框的left和top值
        document.onmousemove = function (e) {
          // 通过事件委托，计算移动的距离 （开始拖拽至结束拖拽的距离）
          const l = e.clientX - disX;
          const t = e.clientY - disY;
  
          let finallyL = l + styL;
          let finallyT = t + styT;
  
          // 边界值判定 注意clientWidth scrollWidth区别 要减去之前的top left值
          let limitL = (document.documentElement.clientWidth - dragDom.clientWidth) / 2;
          if (finallyL < -limitL) {
            finallyL = -limitL;
          } else if (finallyL > limitL) {
            finallyL = limitL;
          }
          let limitT = document.documentElement.clientHeight * 15 / 100;
          let limitB = document.documentElement.clientHeight - dragDom.clientHeight - limitT;
          if (finallyT < -limitT) {
            finallyT = -limitT;
          } else if (finallyT > limitB) {
            finallyT = limitB;
          }
          // 移动当前元素
          dragDom.style.left = `${finallyL}px`;
          dragDom.style.top = `${finallyT}px`;
        };
        document.onmouseup = function (e) {
          document.onmousemove = null;
          document.onmouseup = null;
        };
      };
    }
  })